Echinoid在果蠅精子發育過程中扮演之角色

The role of Echinoid in Drosophila spermatogenesis

陳敬淳(Ching-Chun Chen)

指導教授 ： 徐瑞洲

國立清華大學/生命科學院/分子醫學研究所/碩士(2012年)

https://doi.org/10.6843/NTHU.2012.00132

摘要

果蠅精子形成是由多個發育階段所組成，包括生殖幹細胞分化，精原細胞生長與分裂，精細胞伸長，精細胞individualization，以及精子釋放到儲精囊。在精子形成的最開始，生殖幹細胞進行不對稱分裂，分化出gonialblast。多種機制曾被發現用來將生殖幹細胞保持在hub周圍，其中包括Cadherin所調控的細胞黏著。Gonialblast進行數次分裂與型態變化，形成64個融合(syncytial)而且伸長的精細胞。伸長的精細胞藉由actin cones的移動將細胞膜重組而individualized。果蠅myosin VI曾被發現參與individualization。Individualized精細胞會被coiled並且釋放到儲精囊。Actin caps會將精細胞的核包捆起來，防止未成熟的精子提前被釋放。Echinoid是一個位於adherens junction調控細胞黏著的細胞黏著分子。在本研究中，我們發現ed1X5/edslH8公果蠅有較低的生殖能力，下降的生殖能力可能源自於在individualization與精子釋放過程的發育缺陷。我們也探討了cyst cell在精細胞發育中的調控角色。

關鍵字

果蠅 ； 細胞黏著分子 ； 精子形成

並列摘要

Drosophila spermatogenesis is composed of various developmental stages, including germline stem cell differentiation, spermatogonia growth and division, spermatid elongation, spermatid individualization, and sperm release. At the beginning of spermatogenesis, germline stem cell (GSC) divides asymmetrically to produce gonialblast. Several mechanisms have been found to maintain GSCs at the hub, the GSCs niche, including Cadherin-mediated cell adhesion. Gonialblast undergoes several rounds of division and morphology change to become 64 syncytial and elongated spermatids. Elongated spermatids are individualized through remodeling membranes by movement of actin cones. Drosophila myosin VI has been found to participate in individualization. Individualized spermatid are coiled and released into seminal vesicles. Actin caps bundle spermatid nuclei to prevent premature sperm release. Echinoid is a cell adhesion molecule localized at adherens junction to control cell adhesion. In this study, we found that fertility of ed1X5/edslH8 males is reduced. The reduced fertility may not due to GSCs maintenance but due to developmental failure at individualization and sperm release process. We also examined cyst cell’s control over spermatid development.

參考文獻

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